A plane’s electrical system is a vital and essential component, barring the simplest of aircraft designs. Electrical system capacity and complexity differ significantly between a modern, multi-engine commercial jet aircraft and a light, piston-powered, single-engine general aviation aircraft. Despite this, the electrical systems for aircraft at both ends of the complexity spectrum share many common fundamental components.Any airplane’s electrical system contains components that can generate electricity. Depending on the aircraft, either generators or alternators are used to produce electricity. Normally powered by an engine, they can also be APU, hydraulic, or Ram Air Turbine (RAT) powered. A generator typically produces 115–120V/400HZ AC, 28V DC, or 14V DC. The voltage or type of current can be changed by passing it through transformers, rectifiers, or inverters, or it can be used directly from the generator. Usually, the generator’s output is routed to one or more distribution buses. Circuit breakers or fuses built into the wiring of the component provide circuit protection while individual components are powered from the bus. The generator output (s) are used to provide additional charging for the aircraft battery. NICAD or lead-acid batteries are the most common types of batteries, though lithium batteries are becoming more and more common. In the event that a generation or distribution system fails, they serve as a backup power source and are used to start airplanes. Some single-engine aircraft are not electrically powered. The fuel tank is positioned to feed the piston engine by gravity, and the engine is equipped with a self-powered Magneto ignition system. The engine can be started either with a flywheel and crank or by “hand-proping” it. The desire for an electric starter, lights, electric flight instruments, navigational aids, or radios necessitates the installation of an electrical system. A single distribution bus, a solitary battery, and a solitary engine-powered generator or alternator will likely make up the system’s DC power supply. It will be possible to isolate the battery from the power source thanks to provisions in the form of an on/off switch.